Calculating the Cosmos: Manhattanhenge with Neil deGrasse Tyson and Jackie Faherty

Calculating the Cosmos: Manhattanhenge with Neil deGrasse Tyson & Jackie Faherty

[BUSY CITY STREET NOISES and QUIETLY ENERGETIC PLUCKED STRINGS]

[Busy New York City streets—cars, buildings, and people are all glowing with light from a golden sunset.]

NEIL DEGRASSE TYSON (Frederick P. Rose Director, Hayden Planetarium): You first see a reflection of the sunlight against the buildings on the north side of the street. Those buildings, steel and glass, will reflect the sun. 

[Time lapse of sun setting between a narrow slice of tall buildings, directly in the middle of the street’s vanishing point.]

TYSON: You say, “The sun is coming, it's coming, it's coming.” And then the sun enters the frame. 

[MUSIC SWELLS]

[Astrophysicist Neil deGrasse Tyson speaks from his desk. He wears a suit and tie with an image of space on it. Behind him are models of Earth and Saturn and a poster of NYC labeled “City of Stars”.]

TYSON: That bit of anticipation is always a delight, at least for me.

[Astrophysicist Jackie Faherty wears a dark blazer and speaks in front of a satellite photo of New York City.]

JACKIE FAHERTY (Associate Curator, Department of Astrophysics): Manhattanhenge is a name that we've given to the days of the year when the sun sets perfectly aligned with the grid of Manhattan. 

[The sun sets, perfectly framed by tall buildings. A time lapse view of Manhattan from across the East River. Boats and cars whiz by and the golden sun sets in between buildings.]

FAHERTY: I think Manhattanhenge is really a reminder that we live on this spinning rock that's also moving around the sun in an orbit. 

[Various views of the busy city with people, cars, and buildings backlit by the golden glow of the Manhattanhenge sunset.]

FAHERTY: We have arrived at this position where you could stand in the middle of this great gridded city, take your finger and point it down the middle of 42nd Street, and a line would extend from your arm all the way out 93 million miles to intersect the exact position that the sun is in in that moment. Manhattanhenge is really astronomy in your face.

[The American Museum of Natural History’s logo appears over a shot of 42nd Street during Manhattanhenge. People, extremely close to a line of car traffic, clog the street to get a photo.]

TYSON: If you ask yourself, where does the sun rise each day? 

[Time lapse of the sun rising over an ocean. Time lapse of the sun setting in a desert with tall cactuses on the horizon.]

TYSON: Most people say, oh, it rises in the east and sets in the west. 

[Tyson speaks in his office.]

TYSON: If they give you that answer, it means they’ve never really paid attention to what's going on. Because the rising point of the sun and the setting points of the sun changes daily. 

[An animated visualization shows the setting points of the sun on the Manhattan skyline for many days throughout the course of 2024. The corresponding dates scroll by.]

TYSON: What that means is you can ask yourself, on what day does the sun set aligned with this grid?

[Faherty speaks in front of the satellite image.]

FAHERTY: So I am the official calculator of Manhattanhenge. Every year I do the calculation for the American Museum of Natural History, 

[Faherty speaks to a large crowd in front of a giant movie screen showing a visualization of Manhattanhenge in 3D.]

FAHERTY: …and we officially put out the date and the times for the world. I will look very carefully at the position of the sun and the exact coordinates of the Manhattan grid.

[Various views of the sun setting on the Manhattan skyline.]

[As Tyson speaks at his desk, an animated shape appears. A diameter representing a horizon line is shown on the surface of a sphere. A line indicates a point on that horizon and the word “azimuth” appears.]

TYSON: Generally when you try to identify a place in the sky from where you're standing, you would give its azimuth. That's its point along the horizon. 

[On the same animated sphere, a line stretches on its surface from the horizon up to the top (where the pole would be on a planet). A new line indicates a point on that segment and the word “altitude” appears.]

TYSON: And then you'd give its elevation above the horizon. And those two numbers uniquely place an object on the sky where you're standing.

[A woman looks at a transit map of New York City. The island of Manhattan is oriented vertically on the map.]

TYSON: If you look at a map of Manhattan, we think uptown is north and downtown is south, and that's fine. No one will fault you for that. 

[A compass indicating north, south, east, west appears over an archival map of Manhattan’s street grid. The map rotates in a clockwise direction by about 30 degrees.]

TYSON: But if you really looked it up the borough of Manhattan is actually rotated east of north by about 30 degrees.

[Faherty speaks in front of the satellite image.]

FAHERTY: It's not exactly North-South, so you can't use that as your azimuth direction. 

[Aerial drone shot crossing Manhattan’s grid. Cars drive along the streets below.]

FAHERTY: So Neil deGrasse Tyson went outside and did a measurement of the grid of Manhattan. I went outside and did a measurement of the grid of Manhattan. 

[The animated sphere appears above the archival street map of Manhattan. Text indicates a point on the sphere that is 299.1° in azimuth, and .5° in altitude.]

FAHERTY: And we came to the consensus that 299.1 degrees is our chosen azimuth, and half a degree or a quarter of degree in terms of its altitude. 

[Time lapse of a busy intersection at 42nd Street and 5th Avenue in New York City. Cars race by and pedestrians cross at the crosswalk.]

FAHERTY: The altitude can vary depending on where you are in the city, but I always do the calculation for 42nd Street at Fifth Avenue.

[Slow motion shot of Manhattanhenge from the middle of a street. Pedestrians cross in front of the large glowing sunset.]

FAHERTY: Manhattanhenge happens officially four times a year, One is when the very, very bottom of the sun kisses the grid right before it goes below the horizon. And that's what we call full Manhattanhenge. 

[From across the East River, the sun sets between tall buildings, lending them a reddish glow.]

FAHERTY: Then we have a second kind of event, which is when the midpoint of the sun kisses the grid before it goes below the horizon, and we call that half sun.

[As Faherty speaks to camera, animated graphics appear next to her. One indicating the phenomenon of “half sun” on the grid shows a semi-circle, framed by lines representing tall buildings and bisected by a line indicating the horizon. The other illustrates “full sun” and shows a full circle hanging between the lines representing buildings, its bottom arc just above the line representing the horizon.]

FAHERTY: You have May 28th and 29th for the half sun on the grid and then the full sun on the grid. And then on the other side of the summer solstice, you have the reverse of that. You have full sun on the grid on July 11th, and then half sun on the grid on July 12th.

[Aerial view of Manhattan at sunrise, looking east across the East River to Queens and Brooklyn. Rays of the sun scrape the tops of skyscrapers.]

FAHERTY: There is a similar phenomenon for sunrise. It will happen about six months later, because now you have to wait for the Earth to get all the way around to the other side in its orbit.

[Tyson speaks from his desk.]

TYSON: Here's the problem: looking east for a sunrise, Manhattan ascends. 

[Sunrise over the Roosevelt Avenue cable tramway and a bridge packed with cars. The view of the sun is obscured by the bridge and the ascent of the street.]

TYSON: So, for many vantage points looking due east, you don't actually see the horizon itself. 

[Tyson speaks from his desk.]

TYSON: It's just not as interesting. It's not as striking. Plus, nobody wants to wake up that early.

[Aerial view of Manhattan at night, as a full moon shines over the city lights and reflective skyscrapers.]

TYSON: There would be an equivalent Manhattanhenge for the moon. That would be a setting full moon. But a full moon is full because it is exactly opposite the sun. 

[A full moon appears faintly between two tall buildings in early sunlight.]

TYSON: So you'd be watching a Manhattanhenge just before sunrise, as the full moon being opposite in the sky dips below the horizon.

[Tyson speaks at his desk.]

TYSON: No one stops the car to get out and watch the moon set. It's not a thing. It's not so radiant as the sun is… 

[Rays of the setting sun cascade under an overpass, illuminating the street as cars drive past above.]

TYSON: …to give you that sparkly, photogenic cosmic moment. 

[Rays spill out through buildings as parkgoers watch the Manhattanhenge sunset from a park across the East River.]

TYSON: Nothing would be a striking as Manhattanhenge with the sun.

[A photo of the bright orange sun setting at Manhattanhenge. The Empire State building looms high on the left. Text reads, “First photo of Manhattanhenge. © Neil deGrasse Tyson, 2001. Natural History magazine.”]

TYSON: So my first photo of Manhattanhenge, I stood in the middle of Park Avenue on 34th Street. 

[HAUNTING SOLO TRUMPET]

[Footage of crowds of spectators, many with cameras aiming for a good vantage point on Manhattanhenge. They crowd streets and overpasses as the glowing sun sets in the distance.]

TYSON: What you get is a fascinating vanishing point with all the buildings of steel and glass framing it. This is what makes it a henge. 

[Aerial drone footage of Stonehenge at sunset. The tall stones cast long shadows on the surrounding field.]

TYSON: Stonehenge has vertical stones that, depending on where you look and how they align, they will configure with the sun, moon and stars.

[Wide landscape of the Manhattan skyline as the sun’s rays peek out through the buildings, silhouetting onlookers and illuminating the river.]

FAHERTY: Sunsets and sunrises are parts of the day that we should all prioritize anyway. 

[Various shots of New Yorkers crowding the streets to view Manhattanhenge.]

FAHERTY: And, on the dates of Manhattanhenge, the city comes alive to watch it. People stop on the streets. They ask each other what's going on. They get annoyed, but then they get happy.

TYSON: New Yorkers hardly ever look up. 

[Tyson speaks from his desk.]

TYSON: I think to the extent that we do not look up, we are losing something fundamental to what it is to be alive on Earth, planet Earth, and to have the mental capability to contemplate the cosmos itself. 

[The fiery ball of the setting sun is framed not only by buildings, but by the arms of a spectator who holds up his camera to capture the phenomenon.]

TYSON: You're missing out.

[Credits roll.]